import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {Scanner in = new Scanner(System.in);
	int n = in.nextInt();
	boolean allHorizontal = true;
	boolean allVertical = true;
	int lastHorizontal = 0;
	int lastVertical = 0;
	for (int a0 = 0; a0 < n; a0++) {
	    int x = in.nextInt();
	    int y = in.nextInt();

	    if (a0 != 0 && x != lastHorizontal) {
		allHorizontal = false;
	    }
	    if (a0 != 0 && y != lastVertical) {
		allVertical = false;
	    }

	    lastHorizontal = x;
	    lastVertical = y;
	}
	if (allHorizontal || allVertical) {
	    System.out.println("YES");
	} else {
	    System.out.println("NO");
	}

    }
}